1. Field of the Invention
Embodiments of the invention relate to the field of semiconductor technology, and more specifically, to fuse programming.
2. Description of Related Art
Fuse elements are commonly used in integrated circuits to improve manufacturing yield or customize a circuit. A fuse may be programmed by passing a current with sufficient strength. Fuse programming yield is very sensitive to the transistor strength in the fuse circuit and the resistance value of the fuse element.
Existing techniques for fuse programming have a number of drawbacks. Typically, a single pulse programming is performed. Using single pulse programming, a large process variation in both front end and back end usually results in either under-programming or over-programming from die to die and from wafer to wafer. Under-programming may be caused by a high resistance of the pre-burn fuse element and/or weak transistor. Over-programming may be caused by a low resistance of the pre-burn fuse element and/or strong transistor. Both of the results are undesirable. Under-programming leads to incorrect result because a fuse is not completely blown up. Over-programming may cause collateral damage, leading to low manufacturing yield and reduced reliability.